Richard A Frank

US Patent:

6816351, Nov 9, 2004

Filed:

Aug 29, 2002

Appl. No.:

10/230642

Inventors:

Richard Frank - Longmont CO
Denis Michel Darmon - Longmont CO

Assignee:

National Semiconductor Corporation - Santa Clara CA

International Classification:

H02H 504

US Classification:

361103, 361 938, 374163

Abstract:

A circuit is arranged to provide a thermal shutdown signal in response to an overtemperature condition. The thermal shutdown circuit is typically implemented in the same die as the circuitry that is to be protected. The thermal shutdown circuit provides a first current in response to a change in temperature when a VBE associated with a transistor decreases below a predetermined level. The first current is mirrored to provide a scaled current. A thermal shutdown signal is activated when the scaled current becomes greater than a reference current. The first current is increased in response to the activated thermal shutdown signal such that the thermal shutdown circuit is deactivated at a temperature that is lower than the temperature at which the circuit is activated. The thermal shutdown circuit is deactivated when the temperature of the die decreases.

US Patent:

7397677, Jul 8, 2008

Filed:

Feb 8, 2006

Appl. No.:

11/350674

Inventors:

Michael John Collins - Longmont CO, US
Richard Frank - Longmont CO, US

Assignee:

National Semiconductor Corporation - Santa Clara CA

International Classification:

H02M 3/18
G05F 1/62

US Classification:

363 60, 323271, 327536

Abstract:

A charge pump is provided. The charge pump may include an oscillator, a first switch, a second switch, a capacitor/switch network, an error amplifier, an adjustable resistance circuit, a first switch driver, and a second switch driver. In one embodiment, the first and second drivers each receive the oscillator voltage, and drive the first and second switches, respectively. Further, the adjustable resistance circuit is connected in series with the first and second switch circuits. The charge pump is arranged in a closed loop with the error amplifier driving the adjustable resistance circuit. The resistance of the adjustable resistance circuit is modulated to regulate the output voltage.